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7 .Nov. 12, 1929. WA. SMITH, SR., E! AL 1,734,984

VALVE FOR ROCK DRILLS Filed Feb. 8, 1929 P KL a R qwagtw Q THEIRA TTORNEY Patented Nov. 12, 1929 WILLIAM A. SMITH, SR., OF SAYRE, PENNSYLVANIA, AND WILLIAM A. SMITH, JR., OF I PHILLIPSB'URG, NEW JERSEY, ASSIGL TORS TO INGEBSOLL-BAND COMPANY OF JER- SEY CITY, JERSEY, A CORPORATION OF NEW JERSEY VALVE FOR ROCK DRILLS Application filed February 8, 1929. Serial No. 338,510.

- This invention relates to fluid actuated rock drills, but more particularly to a distributing valve for drills of this type.

The objects of the invention are to obtain a quick and positive action of the valve and consequently a rapid distribution of pressure fluid to the cylinder and to insure the cut off of pressure fluid to the cylinder at the most advantageous period in the cycle of operations of the piston. 1

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawingsillustrating the invention and its application, and in which similar reference characters refer to similar parts,

Figure 1 is a sectional elevation of a portion of a rock drill equipped with a valve cons'tructed in accordance with the practice of the invention and showing the valve in one of its limiting positions, and Figure 2 is a view similar to Figure 1 showing the valve in another limiting position.

Referring more'particularly to the drawings, A represents a drill cylinder having a piston chamber B in which is disposed a reciprocatory hammer piston C. The cylinder A is provided with a free exhaust port D which is controlled by the piston G. 'A head E forms a closure for the front end of the piston chamber B and is provided with a bore F through which extends the shank G of a working implement to receive theblows of the hammer piston C.

In the rearward end of the cylinder A is an enlarged bore H-for the reception of valve mechanism designated generally by J and, as illustrated also a boss K of a back head L which forms a closure for the rearward end of the cylinder A; 1

The back head L may be'secured in operative position on the cylinder A in any suitable manner, asfor instance, by the usual side bolts(not shown) and serves as a housing for a throttle valve 0 whereby the admission of pressure fluid into the drill may be controlled. The throttle valve 0 may be of the rotary type and is provided with a central chamber P which may be in constant communication with a source of pressure fluid supply through a hose or other connect on (not shown). In

the wall of the throttle valve 0 is a port Q, which in the open position of the throttle valve registers with a passage R in the back head L.

The valve chest S which forms a part of the valve mechanism J comprises in this in stance a pair of plates T and U seated in the bore H. The plate U lies in the innermost end of the bore H adjacent the rearward end of the piston chamber B over which it forms a closure. The plate Tv is seated on the plate U and in turn serves as a seat for the back head L.

A valve chamber V is formed in the plates T and U and comprises a reduced portion W formed in this instance entirely in the plate T and an enlarged portion or pressure chamber X which is preferably formed in the rearward surface of the plate U.

' Pressure fluid for actuating the piston C is conveyed from the valr e chamber V by inlet passages Y and Z. The inlet passage Y leads from a point near the rearward end of the reduced portion W of the valve chamber through the plates T and U and opens into the rearward end of the piston chamber B. The inlet passage Z leads from the forward end of the pressure chamber X to the front end of the piston chamber B and in this instance has a rearward extension Z) which opens into the reduced portion W of the valve chamber at a point intermediate its ends.

The distribution of pressure fluid to the ends of the piston chamber is effected by a distributing valve 0 disposed in the valve chamber V. The distributing valve 0 comprises a body portion d reciprocable in the reduced portion WV and a flange e which extends slidably into the pressure chamber X. The valve 0 in this instance has a central pas sage 7 which is in constant communication with the passage R and therefore constantly supplied with pressure fluid. In the front end of the valve and opening from the passage f is a supply passage 9 through which pressure fluid flows into the front end of the pressure chamber X for supplying the front end of the piston chamber B.

The valve 0 is provided with rearward and forward actuating surfaces It and respectively. The rearward actuating surface 71, is constantly exposed to pressure fluid tending to throw the valve forwardly and the pressure fluid to the rearward end of the piston chamber B flows over the said actuating surface h. The forward actuating surface is of greater area than the actuating surface it and is exposed only intermittently to pressure fluid for throwing the valve 0 rearwardly for admitting pressure fluid to the front end of the piston chamber. To this end the cylinder A is provided with a tripper passage which leads from the pressure chamber X to a point near the front end of the piston chamber B. The point at which the tripper passage 7c may open into the piston chamber B may be determined by the specific requirements of the drill. It should, however, open into the piston chamber at a point within the range of travel ofthe piston C so that pressure fluid flowing into the tripper passage h from the supply passage 9 through a leak passage 0 in the plate U will be entrapped in the tripper passage 70 to act against the actuating surface for throwing the valve 0 rearwardly. By changing the position of the outlet opening of the tripper passage either forwardly or in a rearwardly direction the valve may be thrown eitherearly or late as desired. I

Leading from the reduced portion WV of the valve chamber V is a. compression relief port 10 which is in constant registry with a groove 9 in the body portion of the valve and which groove is adapted to establish conmunication between the inlet passage Y and the compression relief port p and between the extension 6 of the inlet passage Z and the compression relief. port p for exhausting compression from the ends of the piston chamber to the atmosphere.

The following is a brief description of the operation of the device. WVith the valve 0 in the forwardmost limiting position illustrated in Figure 1, pressure fluid will flow over the actuating. surface h into and through the inlet passage Y into the rearward end of the piston chamber B to drive the piston C forwardly against the working implement. In this posit-ion'of the valve pressure fluid will be constantly flowing through the passage f and the supply passage 9 in the valve, thence through the leak passage 0 into the tripper passage is and into the front end of the piston chamber. l/Vhile the piston is in the rear wardmost position illustrated in Figure 1 such pressure fluid will'of course escape to the atmosphere through the exhaust port D. After the piston C overruns the exhaust port D however, the pressure fluid flowing through the tripper passage into the front end of the piston chamber B together with the compression created by the piston will pass through the inlet passage Z and the extension I) into the reduced portion W of the valve chamber and thence through the groove q in the valve and through the compression relief port 39 to the atmosphere.

The relief of pressure in the front end of the piston chamber will continue until the piston C covers the outlet opening of the tripper passage in. Immediately after this occurs the pressure fluid entrapped in the tripper passage is will act against the actuating surface j of the flange 6. then this pressure reaches a value in excess of that acting against the actuating surface h the valve 0 will be thrown rearwardly. This shifting of the valve may take place substantially simultaneously with the delivery ofthe blow of the hammer piston against the wor ing implement. v

By shifting thevalve to the'positi'on illustrated in Figure 2 the flow of pressure fluid to the rearward end of the piston chamberwill of course be out off, although the actusting surface it will still be exposed over its entire area to live pressure fluid. Pressure fluid will then flow throughthe valve into the front end of the pressure chamber X and thence through the front inlet passa e Z to the front end of the piston chamber to drive the piston C rearwardly." During the rearward travel of the piston the compression created in the rearward end of the piston chamber B will flow through the rearward inlet passage Y into the valve chamber, thence through the groove 9 in the valve-and: the compression relief port p to the atmos phere. After the piston C uncovers the exhaust port D the pressure fluid utilized for actuating the piston rearwardly w'ill'be exhausted to the atmosphere: and the pressure forwardly of the. valve will then drop -to-enable that acting against the rearactuating surface it to again return'the valve to its initial position. a

e claim: 7

1. In a fluid actuated rock drill, theicoms bination of a cylinder and a piston in the cylinder, an exhaust port in the cylinder, a valve chamber, inlet passages leading from the valve chamber to the cylinden a" valve in the valve chamber having "anactuat'ing sur face constantlyexpo'sed to pressure fluid for throwing the valve in one direction and over which pressure fluid flows to one inlet passage, a supply'passage in the valve for conveying pressure fluid to the other inlet pas sa go, a second actuatingsurface-on the valve, and a tri-pper passage in the cylinder in constant communicationwitlrthe supply pas sage and adapted tobe covered by the piston, thereby entrapping pressure fluid'in t'he'tripper passage to act against the second said actuating surface for throwing the val'vein the opposite direct-ion.-

2. In a fluid actuated rock drill, the com bination of a cylinder and a piston in- "the cylinder, an exhaust port in the cylinder coniso trolled by the piston, a valve chamber, inlet passages leading from the ends of the valve chamber to the cylinder, a valve in the valve chamber having an actuating surface at one end constantly exposed to pressure fluid for throwing the valve in one direction and over which pressure fluid flows to one inlet passage, a supply passage in the valve constantly exposed to pressure fluid for supplying pressure fluid to the other inlet passage, an actuating surface at the other end of the valve, and a tripper passage in the cylinder in constant communication with the supply passage and adapted to be covered by the piston, thereby entrapping pressure fluid in the tripper passage to act against the second said actuating surface for throwing the valve In the other direction.

3. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder,an exhaust port in the cylinder controlledby the piston, a valve chamber having an enlarged pressure chamber, inlet passages leading from the ends of the valve chamber to the cylinder, a valve in the valve chamber having a flange extending into the pressure chamber, an actuating surface at the rearward end of the valve constantly exposed to pressure fluid and over which pressure fluid flows to one inlet passage, a supply passage in the valve constantly exposed to pressure fluid for supplying pressure fluid to the other inlet passage, an actuating surface on the front end of the valve and of greater area than the first said actuating surface, and a tripper passage leading from the cylinder to the pressure chamber, said tripper passage being in constant communication with the supply passage and adapted to be covered by the piston, thereby entrapping pressure fluid in the pressure chamber to act against the actuating surface of greater area for throwing the Valve in the other direction.

4. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder, an exhaust port in the cylinder controlled by the piston, a valve chamber having an enlarged pressure chamber, inlet passages leading from the ends of the valve chamber to the corresponding ends of the cylinder, a valve in the valve chamber having a flange extending into the enlarged pressure'chamber, an actuating surface on the rearward end of the valve constantly exposed to pressure fluid for throwing the valve in one direction and over which pressure fluid flowslto one inlet passage, a supply passage in the valve constantly exposed to pressure fluid for supplying pressure fluid to the other inlet passage, an actuating surface on the front end of the valve and of greater area than the first said actuating surface, a tripper passage leading from the pressure chamber to the cylinder and adapted to be covered by the piston, and a bleeder passage constantly conveying pressure fluid from the supply passage to the tripper passage wherein pressure fluid is entrapped when the piston covers said tripper passage to act against the actuating surface of greater area for throwing the valve in the opposite direction.

5. In a fluid actuated rock drill, the combination of a cylinder and a piston in the cylinder, an exhaust port in the cylinder controlled by the piston, a valve chamber having an enlarged pressure chamber, inlet passages for conveying pressure fluid from the valve chamber to the cylinder and for conveying compression fromv the cylinder to the valve chamber, a compression relief port leading from the valve chamber to the atmosphere, a valve in the valve chamber having an actuating surface constantly exposed to pressure fluid for throwing the valve in one direction and over which pressure fluid flows to one inlet passage, a flange on the valve extending into the enlarged pressure chamber and having an actuating surface of greater area than the first said actuating surface, a tripper passage leading from the pressure chamber to the cylinder and adapted to be covered by the piston, a bleeder passage constantly conveying pressure fluid from. the supply passage into the tripper passage wherein pressure fluid is entrapped when the piston covers said tripper passage to act against the actuating surface of greater area for throwing the valve in the other direction, and a groove in the valve for establishing communication between the inlet passages and the compression relief port.

In testimony whereof we have signed this specification.

WILLIAM A. SMITH, SR. WILLIAM A. SMITH, JR. 

